In a railway station, a bus stop or in an airport, for example, various kinds of information have been provided to users using posters or announcement in many cases. With the development in computer systems and video systems in recent years, however, it has been allowed to provide these kinds of information to the users as video information and audio information.
FIG. 6 is a block diagram illustrating the structure of an information display system in the background art (see Japanese Patent Publication No. 2569025). With reference to FIG. 6, the background-art information display system has a control unit 900, and a display device 941 and a ticket vending machine 942 with display device each controlled by the control unit 900. The control unit 900 includes an image transmission line 952, a data transmission line 951, a communication controller 911, a control calculator 901, a control communication line 912, a keyboard 902, a monitor 903, a fixed disk 904, a printer 905, controllers 921, 923, an image memory 925, a video tape recorder 922, a video disk 924, a video signal converter 926, and a signal switching device 931. The control unit 900 is placed at each railway station. The ticket vending machine 942 with display device is placed at a ticket counter in a railway station. The display device 941 is located in a passenger car of a train or at a platform of a station.
Next, operations of the background-art information display system given in FIG. 6 will be described. Various types of images to be provided to the users are stored in advance in each of the video tape recorder 922, the video disk 924 and the image memory 925. On the basis of control instructions inputted by an administrator of this information display system (information provider) using the keyboard 902, the control calculator 901 controls operations of the devices such as the controllers 921, 923 and the signal switching device 931. In response to channel switching operation of the signal switching device 931, the images stored in each of the video tape recorder 922, the video disk 924 and the image memory 925, or images transmitted from outside through the image transmission line 952 are thereby displayed on the display device 941 and the ticket vending machine 942 with display device and provided to the users.
According to the background-art information display system given in FIG. 6, however, only the information provider is allowed to change information in the control unit 900 displayed on the display device 941 and the ticket vending machine 942 with display device. Therefore, even in the case such as emergency where change to the information provided to the users should be immediately reflected, the information provider should change information on receipt of notification from the users, for example. Change to the information requires control of the signal switching device 931 using the keyboard 902 and replacement of the devices such as the video tape recorder 922 in the controller 900, taking long time to reflect change to the information.